Wood grinding machine



March 3, 1959 H.A I WENDSHUH woon GRINDING MACHINE 2 sheets-she'et 1 Filed Nov. 14, I 195e v \\gmmw March 3, 19'59"' v H. L. wENDsHUH 2,875,957

WOOD GRINDING MACHINE Filed Nov. 14,1'95e 2 sheets-sheet 2 WOOD GRINDING MACHINE Herbert L. Wendshuh, Appleton, Wis., assignor to The `Appleton Machine Company, a corporation of Wisconsin Application November 14, 1956, Serial No. 622,225

Claims. (Cl.vr 241,97)

This invention relates to a wood grinding machine having a return plate for carrying shims from the discharge end of the grinding zone back to the feed end of the grinding machine, and is particularly concerned with means to` wash the shims to prevent carrying stock adhering to the shims back to the feed end of the machine, and also to lubricate the shims as they are moved across the return plate back to the feed end of the machine.

The wood grinding machine .comprises a feed ring rotatably mounted in a cylindrical housing, and a grinding stone eccentrically mounted within the feed ring. The grinding stone .cooperates with the feed ring to grind logs into paper stock. The paper stock, which comprises about 2% ground wood and 98% water, vilows through openings provided in the feed ring and into a discharge chute. The stock washed from the shims before they are carried back to the feed end of the machine mixes with the stock flowing through the openingsin the feed ring and into the discharge chute.

The feed ring of the present invention is cylindrical and its outer edge portion is rigidly secured to a ring gear which is rotated slowly by a pinion. Two parallel series of shoes' of plastic material, for 'example a phenol-formaldehyde condensation product such as is presently available under the trademarks Micarta and Bakelite, or other suitable material, are 'mounted on the outer surface of the feed ring. The shoes extend around theA entire circumference ofthe feed ring and formk substantially continuous bearing surfaces `for the feed ring. The Ybearing surfaces are lubricated automatically as the feed ring is rotated.V

The shoes may be removed and replaced individually, as they become worn, without dismantling the machine.

The bottom case of the housing has a pair of grooves into which the bearing shoes t to prevent lateral displacement of the lower portion of the feed ring. The upper portion of the feed ring is stabilized by one or more pairsv of guide rollers rotating about an axis at right angles to the axis of rotation of the feed ring.

The feed ring is rotated in the same direction as the grinding stone to force the logs toward the stone, thereby obtaining the grinding-action required. The inner surface ofthe feedA ring is roughened to cooperate with the peripheral surface of the grinding stone to provide eicient grinding of the wood` The bottom case of the housing is provided with a discharge outlet for vthe paper stock at each side of the machine. Perforated baie plates at opposite sides of the feed ring permit the iiow of the paper stock into the discharge chute without permittingshims to pass through. The feed ring is also provided with openings leading directly to the discharge chute. v

A series of jet nozzles aligned with the openings in the feed ring serve to flush out the openings and prevent them from becoming clogged. A pair of deckle strapssecured to the housing cover the gap between the housing and the edge of the feed ring to preventthe water from flowing past the bearings-and into the gearing. lf the deckle.

j 2,875,957 Patented Mar. 3*, 1959 ice ` straps should allow passage of water, the bearings would prevent such water from reaching the gears.

The shims are carried around by the feed ring and grinding stone to a doctor blade which is positioned near one edge of a return plate. The doctor blade removes the wood shims from the grinding stone and directs them ybetween the return plate and the feed ring. The rough surface of the feed ring carries the shims across the machine where they are dropped at the feed end so that they may be again carried through the grinding operation. As the doctor blade moves the shims to the return plate they are washed by a jet shower interposed between said doctor and the return plate. The jet shower washes oft' the stock that has adhered to the shims and sends it directly to the stock discharge, rather than letting the feed ring carry it back to the feed end of the machine along with the shims for regrinding.

The structure by means of which the above and other advantages are attained will be described in detail in the following specication, taken in conjunction with the accompanying drawings, showing a preferred illustrative dicates a base having a pair of parallel flat surfaces 3 upon which a cylindrical housing 4 is supported. Housing 4 is made in two parts, an upper case 5 and a bottom case 6` having abutting iianges 7 secured together in any suitable manner after the rest of the machine is assembled. Surfaces 3 extend beyond each end of the housing and are separated by a channel 8 open at itstop to receive a bulged wall portion 9 projecting outwardly from thecenter portion of the housing around its entire periphery. y

On opposite sides of the bulge 9, the housing has a pair of ilat surfaces 10 in engagement with the ilat surfaces 3.

A screw 11 journalled lin a bearing in standard 12,

mounted on one end of the base, is provided with a lever 13, by which it may be turned to move the housing 4 on base 2. This movement of the housing is for the purpose of compensating for the wear on the grinding stone, hereinafter described, and is limited in extent.

Two standards 14 at opposite sides of housing 4 support bearings 15 in alignment with each other along an axis eccentric to the center of housing 4. A shaft 16 journalled in bearings 15 extends through openings provided therefor in the side walls 17 of housing 4. Shaft 16 is rotated by a motor (not shown). A grinding stone 18 is mounted on shaft 16 to rotate therewith.v The grinding stone is smaller in circumference than the interior of housing 4, and its axis is eccentric relative to the center of housing 4. The peripheral surface of the grinding stone engages the inner surface of the feed ring, hereinafter described, during a portion of its rotation to form a grinding zone in which the Wood logs are substantially ground to paper stock.

The width of grinding stone 18 is less than the width of the housing 4, as shown in Fig. 3. The grinding stone is centered laterally, relative to the housing, by a pair of collars 19 which prevent any lateral movement of the grinding stone on shaft 16. A bacie plate 20 is held adjacent each side of the grinding stone by a plurality of rods 21, each threaded through an aperture in wall 17 and engaging a boss 22 projecting outwardly from the baffle plate. A nut 23, threaded on each rod 21, is tightenedl against Wall 1'7 to hold the baille plate Vadjacent the vside of `grinding stoney 18 with just enough clearance to allow theV grinding stone to rotate freely.

Both baille plates 20 are alike and the description of one will apply to the other as well. As shown in Fig. 2, the baille plate extends from the bottom of housing 4 to a point above the axis of the grinding stone. One edge of the baille plate is curved to conform to the configuration of the inner surface of housing 4. The other edge' of the baille plate is curved to conform generally to the peripheral edge of the grinding stone which it overlaps slightly. A plurality of perforations 24 extend through the bailleI plate to allow paper stock to pass therethrough into'the space between the baille plate and the adjacent side wall 17 of the housing. The space between thc baflle plate and side wall 17 forms part of a discharge chute 25 which extends from one end of the housing.

A ring gear 26, having teeth 27 on its outer surface, is rotatably mounted within the peripheral bulge 9 of' housing 4. Housing 4 is provided with an openingV 28r (Fig. 2)` aligned with gear 26. A gear 29, mounted on a shaft 30 adjacent opening 28 projects through the opening into 'mesh with gear teeth VA27. A motor 31 mounted on the outside of housing 4 rotates shaft 30 and, through it and gear 29, the ring gear 26. A cover member 32 is provided on the outside of housing 4 to serve as a housing for gear 29. Ring gear 26 is T-shaped and has a centrally located flange 33 extending inwardly therefrom.

A lfeed ring 34, mounted within housing 4, is secured to flange 33` and rotates with the ring gear. The feed ring comprises two sections 35 and 36 (Fig. 3) for convenience of assembly. The inner edges of both sections are offset, as indicated at 37, to facilitate alignment of the two sections, 'and each section is provided with a peripheral ilange 38 set back from its inner edge a distance equalto half the thickness of flange 33. Flanges 38" tt'on opposite sides of flange 33, and all three flanges are provided with Vregistering apertures to receive bolts 39 by means of which the feed ring sections are both secured to each other and to the ring gear. Both sections of the feed ring are alike, so only one section will be described, the same reference numerals being applied to both sections.

Bearing shoes 40 are secured to the periphery of feed ring 34 in end to end relationship to furnish a continuous bearing surface. The shoes may be of plastic, for example, a phenol-formaldehyde resinous condensation product such as that sold under the trademark Ryertex or the trademark Insurok, or any other suitable material. Each shoe is in the form of a generally rectangular block curved slightly in its longitudinal direction to fit against the outer surface of the feed ring which is grooved, as indicated lat 41, to provide a seat for the shoes. If any shoe becomes worn it may be removed and replaced without disturbing the adjacent shoes.

The bottom case 6 of housing 4 is provided with a circumferential groove 42 on its inner surface which serves as a guide for bearing shoes 40, which lit in said grooves, during their movement around the lower half of the housing. The grooves 42 cooperate with shoes 40 to prevent any llateral displacement or tipping of the lower half of the feed ring.

The upper half of the feed ring is stabilized by rollers 43 which abut the lateral edges of the feed ring and are rotatable about an axis perpendicular to the axis of rotation of the feed ring. Each roller 43 has a shaft 44 which projects through an opening 45 in the housing. A support 46 holds each roller 43 against vertical displacement. A set screw 47, extending through a bracket 48 positioned adjacent the outer surface of housing 4, exerts lateral pressure against each support 46 to rnaintain roller 43 in juxtaposition with the side of feed ring 26 with a suitable lateral pressure.

l width of the grinding stone 18, into the machine. Any suitable door may be mountedr on the housing to serve as a closure for opening 49. The water necessary for the grinding operation is fed into the machine by a perforated pipe 50 extending transversely of the housing above the grinding stone. The inner surface of feed ring 34 is provided with transverse and circumferential I ribs 51 projecting inwardly therefrom to engage the logs in the machine and move them toward the grinding zone.

The outer edges and the outer periphery of feed ring 34 are formed, as indicated at 51, Fig. 3, to provide a space 52 between the feed ring and the housing 4. This l space 52 forms part of the discharge chute 25. The feed ring is provided with three transversely spaced series of openings 53, 54 and 55. The openings 53, 54 and 55 extend through the feed ring angularly so that each opening leads to the space 52. The paper stock, in the form j of a mixture of finely ground wood and water, thatis Housing 4 is provided with lan opening 49 in the upper discharged through these openings at the bottom of the feed ring, ows into the space 52.

ln order to prevent the openings 53, 54 and 55 from becoming clogged, a water hose 56, provided with three jet nozzles 57, 58 and 59, is mounted on the outside of the housing. Each nozzle is aligned angularly with one of the openings 53, 54 or 55, and is positioned close to the feed ring so that water from each nozzle llushes out the openings of one of the series of openings.

The paper stock is prevented from flowing into engagement with either the bearing shoes 40 or the ring gear 26 by means of a deckle strap 60 which extends around the bottom case of housing 4 to cover the gap between the housing and the edge of feed ring 34 adjacent the inner edge of space 52. The ends of the deckle strap are rigidly secured to the upper case of housing 4 in any suitable manner. The means for securing the deckle strap is adjustable so that the deckle strap may be kept taut in order to form an effective Water seal. If any water does pass the deckle strap it will be stopped by the bearing shoes 40 and will do no real damage, since it ycannot reach the gear 26.

A doctor blade 61 is pivotally mounted in housing 4, as indicated at 62, with its bevelled end 63 adjacent the periphery of grinding stone 18 just beyond the grinding zone. The doctor blade extends across the entire width of the housing and removes any wood shims that might otherwise stick to the grinding stone and impair its efciency. These shims are generally repelled by the stone.

However, shouldfthey have a tendency to adhere to thek stone, the doctor blade lacts as a stripper, causing the shims to be moved outwardly against the ribbed surface of feed ring 34. Some of the finely ground wood often clings to the shims and is not separated therefrom even by the centrifugal force of the grinding stone which tends to throw the shims against the feed ring.

A return plate 64 curved to conform to the curvature ofthe feed ring extends across the entire width of the housing and has its outer edges secured to sidewall 17 of the housing, as indicated at 65. The return plate 64 cooperates with the feed ring 26 to form a passageway for the retum of the shims from the discharge end of the grinding zone to the feed end of the machine. of plate 64 is positioned just above the top of doctor blade 61 so that shims directed outwardlypfrom the doctor blade are caught in the passageway between the plate 64 and the feed ring 34, and cannot drop until they are over the feed end of the machine. This arrangement insures re-grinding of the wood shims. However, these wood shims often havey valuable paper stock clinging to them as they are moved from the grinidng stone. It is de sirable to movey this paper stock into the discharge area of the machine where it will intermingle with the paper stock llowing through the apertures 53, 54 and 55 of the feed ring.

A shower pipe 66, positioned adjacent the upper edge of doctor blade 61, is provided with a plurality of jet One edge openings 67 adapted to direct a multiplicity of sprays of water between the edge of plate 64 and the upper edge of doctor blade 61. The water sprays from shower pipe 66 engage the wood shims as they pass from the doctor blade 61 to the passageway between the feed ring 34 and the return plate 64 and wash away any paper stock clinging thereto. The stock washed from the shims falls directly into the discharge area, instead of being carried with the shims around the return plate to the feed end of the grinding machine. Accordingly, the grinding zone may accommodate unground wood up to its full capacity.

The rapid rotation of the grinding stone 18 and the friction of the doctor blade 61 as it removes the shims from the grinding stone and throws them against the feed ring 34 tends to dry the shims. In addition to washing the valuable paper stock from the shims, the shower from pipe 66-also wets the shims, and thereby lubricates them to facilitate their movement over the return plate back to the feed end of the grinding machine.

The operation of the machine will now be described. The logs are loaded into the machine through opening 49 and water is fed through pipe 50. The grinding stone and feed ring are rotated in the same direction, i. e. clockwise as viewed in Fig. 2, but at different speeds. The internal ribs 51 on the feed ring engage the logs and move them toward the underside of the grinding stone. Since the logs cannot move backwards, they remain in the grinding zone between the inner surface of the feed ring and the peripheral surface of the grinding stone until they are substantially completely ground.

The shims small enough to pass through the small clearance between the peripheral surfaces of the feed ring and the grinding stone are either thrown from the grinding stone directly against the ribbed surface of the feed ring by centrifugal force or are scraped from the stone by the doctor blade. The shims scraped from the grinding stone by the doctor blade are also thrown against the ribbed surface of the feed ring by centrifugal force. The paper stock clinging to the shims is washed olf by the Water sprays from shower pipe 66 as the shims pass between the doctor blade and the edge of plate 64 which denes the start of the passageway between the feed roll and the return plate. The paper stock washed from the shims falls directly into the discharge area. VThe shims, with the paper stock washed therefrom, are moved by the ribs 51 across the upper half of the housing, and then mixed with the logs introduced through the opening 49.

The paper stock, which comprises approximately 2% ground wood and 98% water, ows through openings 53, 54 and 55 into space 52 and then into discharge chute 25. Additional stock ows through perforations 24 in baille plate 20 into the discharge chute 25.

The bearings 15 in which the shaft of the grinding stone is mounted are stationary. Accordingly, as the grinding stone becomes worn the space between its peripheral surface and the inner surface of the feed ring increases. In order to prevent too great an increase in the clearance between the grinding stone and the feed ring, the screw 11 is turned to move the housing to the right, as seen in Figs. 1 and 2, to restore the clearance space to the desired dimension. The housing is moved to the left when the grinding stone is to be replaced by a new stone. The sectional structure of the housing permits the side walls 17 to be removed for removal or insertion of the grinding stone, and the upper case of the housing to be removed for removal or insertion of any of the bearing shoes 40.

While I have described a preferred embodiment of my invention in considerable detail, it will be understood that the description is intended to be illustrative, rather than restrictive, as many details may be modifiedV or changed 6 without departing from the spirit or scope of my invention. Accordingly, I do not desire to be restricted to the exact details of construction described.

I claim:

l. A Wood grinding machine comprising a housing, a feed ring rotatably mounted in said housing, a grinding stone cooperating with said feed ring to form a grinding zone, a' return plate spaced from said grinding zone, said return plate cooperating with said feed ring to form a passageway for the return of shims from the discharge end of said grinding zone to the feed end of said machine, means for moving shims from the discharge end of said grinding Zone to said passageway, and a shower pipe arranged to spray water toward the shims as the shims pass across the space between the discharge end of said grinding zone and said return plate.

2. A Wood grinding machine comprising a housing, means within said housing for grinding logs into paper stock, a doctor blade for removing shims from said grinding means, a return plate spaced from said doctor blade, said return plate being adapted to receive shims removed from said grinding means by said doctor blade, and means for spraying said shims with water as they are moved from said doctor blade to said return plate.

3. A wood grinding machine comprising a housing, a feed ring and a grinding stone rotatably mounted in said housing to form a grinding zone, means for rotating said feed ring and grinding stone to grind logs in said grinding zone into paper stock comprising a mixture of ground wood and water, a doctor blade having a thin edge positioned adjacent the peripheral surface of said grinding stone beyond the end of said grinding zone, a return plate having one edge spaced from 'the opposite edge of said doctor blade, and a shower pipe extending across the width of the machine and adapted to spray water between said one edge of said return plate and said doctor blade.

4. A Wood grinding machine comprising a housing, a feed ring rotatably mounted in said housing, a grinding stone eccentrically mounted within said feed ring with one portion of the peripheral surface of said grinding stone engaging a portion of the inner surface of said feed ring to form a grinding zone for grinding logs into paper stock, a doctor blade positioned adjacent the peripheral surface of said grinding stone beyond said grinding zone and adapted to remove shims from said grinding stone, a return plate having one edge adjacent said doctor blade, said return plate cooperating with said feed ring to provide a passageway for the return of shims from the discharge end of said grinding zone to the feed end of said machine, means for moving said shims from said doctor blade to said passageway, and a shower pipe for spraying water between said doctor blade and said one edge of said return plate.

5. A wood grinding machine comprising a feed ring and a grinding stone adapted to cooperate to grind logs into paper stock, a discharge area for said paper stock, means for removing shims from said grinding stone, and a water spray directed at said shims as they are removed by said means from said grinding stone to wash paper stock from said shims into said discharge area.

References Cited in the le of this patent UNITED STATES PATENTS 1,061,316 Nase May 13, 1913 2,406,904 Roberts Sept. 3, 1946 2,642,231 Illig .Tune 16, 1953 FOREIGN PATENTS 138,820 Germany Jan. 23, 1902 4384,731, .Germany Mar. 28, 1922 

